It's a reference to the early animation tactic of looping the background art over and over to show continuous progress without drawing more scenery. George is driving in a circle around the wall segment, also looping the background over and over.

"Steamboat Willie" was the name of the first Mickey Mouse cartoon from Disney. As mentioned, the animators looped the same background art past repeatedly to create the illusion of continuous motion over a long distance, kind of like what George was doing by circling the silo.